Experimental study of turbulent convective heat transfer and pressure drop of dilute CuO/water nanofluid inside a circular tube

Turbulent convective heat transfer performance and pressure drop of very dilute (less than 0.24% volume) CuO/water nanofluid flowing through a circular tube were investigated experimentally. Measurements showed that addition of small amounts of nanosized CuO particles to the base fluid increased heat transfer coefficients considerably. In average 25% increase in heat transfer coefficient was observed with 20% penalty in pressure drop. Enhancement ratio did not show significant variation with concentration of CuO in nanofluid in the range studied in this work. Flow resistance increased significantly compared to base fluid even at very low concentrations of CuO. Measured heat transfer coefficients were compared with predictions obtained from different correlations proposed for heat transfer coefficients of nanofluids. The correlation proposed by Buongiorno predicted experimental data nicely. (C) 2009 Elsevier Ltd. All rights reserved.